package com.moli.filter;

import com.alibaba.fastjson.JSON;
import com.moli.common.BaseContext;
import com.moli.common.R;
import lombok.extern.slf4j.Slf4j;
import org.springframework.util.AntPathMatcher;
import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * 检查用户是否已经完成登录
 */
@WebFilter(filterName = "loginCheckFilter",urlPatterns = "/*")//拦截所有请求
@Slf4j
public class LoginCheckFilter implements Filter{
    //路径匹配器，支持通配符
    public static final AntPathMatcher PATH_MATCHER = new AntPathMatcher();

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        //1、获取本次请求的URI，就是要拦截的url
        String requestURI = request.getRequestURI();
        //定义不需要处理的请求路径
        String[] urls = new String[]{
                "/employee/login",
                "/employee/logout",
                "/backend/**",//不用拦截前端页面的原因是:最主要是不让外部人员看数据，主要是拦截通过controller访问的路径
                "/front/**",
                "/user/sendMsg",//发送验证码的页面
                "/user/login"//前端登录页面
        };

        //2、判断本次请求是否需要处理
        boolean check = check(urls, requestURI);

        //3、如果不需要处理，则直接放行
        if(check){
            log.info("本次请求{}不需要处理",requestURI);//{}相当于占位符，后面的就会在占位符上输出
            filterChain.doFilter(request,response);
            return;
        }

        //4-1、判断登录状态，如果已登录，则直接放行
        if(request.getSession().getAttribute("employee") != null){
            log.info("用户已登录，用户id为：{}",request.getSession().getAttribute("employee"));

            /*看线程情况
            long id = Thread.currentThread().getId();
            log.info("线程id为：{}",id);*/

            //获取id，便于同线程的使用
            long empid = (long) request.getSession().getAttribute("employee");
            BaseContext.setCurrentId(empid);

            filterChain.doFilter(request,response);
            return;
        }
        //4-2、判断登录状态，如果已登录，则直接放行
        if(request.getSession().getAttribute("user") != null){
            log.info("用户已登录，用户id为：{}",request.getSession().getAttribute("user"));

            Long userId = (Long) request.getSession().getAttribute("user");
            BaseContext.setCurrentId(userId);

            filterChain.doFilter(request,response);
            return;
        }

        log.info("用户未登录");

        //5、如果未登录则返回未登录结果
        log.info("拦截到请求：{}",requestURI);
        response.getWriter().write(JSON.toJSONString(R.error("NOTLOGIN")));//通过输出流方式向前端客户端页面request.js响应数据
        return;
    }

    /**
     * 路径匹配，检查本次请求是否需要放行
     * @param urls
     * @param requestURI
     * @return
     */
    public boolean check(String[] urls,String requestURI){
        for (String url : urls) {
            boolean match = PATH_MATCHER.match(url, requestURI);//匹配url和我们请求的url是否相同
            if(match){
                return true;
            }
        }
        return false;
    }
}
